Rendering fibrous material flame retardant

ABSTRACT

WHEREIN R1 represents a monovalent radical such as hydrogen or methoxy and R2 represents a monovalent radical such as hydrogen or methyl. Durability of the flame retardancy to repeated hard water washing may be improved through a subsequent treatment with N-methylol compounds or with additional cyanamide or by methylation with diazomethane. Dimensional stability and durable press properties of cellulosic textiles are also improved by the subsequent treatment with additional cyanamide. A particularly high degree of flame retardancy is imparted to mercerized cotton cloth.   Fibrous material such as cotton cloth is rendered flame retardant by treating the material with cyanamide and at least one phosphonic acid represented by the structural formula:

Swidler et al.

1 RENDERING FIBROUS MATERIAL FLAME RETARDANT [75] Inventors: Ronald Swidler; William A.

Sanderson, both of Palo Alto; William A. Mueller, Pasadena, all of Calif.

[73] Assignee: Cotton Incorporated, New York,

122] Filed: July 2, 1973 121] Appl. No.: 375,439

Related U.S. Application Data [63] Continuation-impart of Ser. No. 259.350, June 2, 1972, abandoned, which is a continuation of Ser. No. 153,094. June 14, 1971, abandoned, which is a continuation of Ser. No. 862,509, Sept. 30, 1969, abandoned.

[52] U.S. Cl. 117/136, l17/l39.4, 106/15 FP, 252/8.l [51] Int. Cl C09k 3/28 [58] Field of Search 117/136, 143 A, 139.4, 117/137; 106/15 FP; 252/8.l; 260/5024 R, 502.4 P, 928. 941, 953, 961

[56] References Cited UNITED STATES PATENTS 2.530.261 11/1950 Morton et a1 8/1 16.2 3,322,716 5/1967 Klein et a1 260/5024 R Apr. 1, 1975 Primary E.\'aminerCharles E. Van Horn Assistant ExaminerNeal Kalishman Attorney, Agent, or FirmBurns, Doane, Swecker & Mathis [57] ABSTRACT Fibrous material such as cotton cloth is rendered flame retardant by treating the material with cyanamide and at least one phosphonic acid represented by the structural formula:

H 0 OH 21 Claims, No Drawings RENDERING FIBROUS MATERIAL FLAME RETARDANT CROSS REFERENCE TO RELATED APPLICATIONS This is a continuation in part of copending application Ser. No. 259,350, filed June 2, I972, now abandoned which in turn is a continuation of application Ser. No. l53,094, filed June 14, l97l,now abandoned, which in turn is a continuation of Ser. No. 862,509, filed Sept. 30, 1969, now abandoned.

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to flame retardant fibercontaining material and to processes for producing the same.

3. State of the Art Natural fiber-containing textile materials such as cotton cloth have beem employed since ancient times. However. the combustibility of these textile materials has inhibited their wider use in certain instances. A great number of flame retardants have been proposed for use with cellulosic textile materials, but these flame retardants suffer from one or more disadvantages.

A major disadvantage of many prior flame retardants is their lack of wash fastness or durability, by which is meant that while they initially render the cellulosic textile material flame retardant, such flame retardancy disappears after one or more household launderings, especially in hard water. This phenomenon is described by OBrien in Cyanamide-Based Durable Flame- Retardant Finish for Cotton," Textile Research Journal, Mar. 1968. pp. 256266. This article describes the treatment of cellulosic textile materials with flame retardants of cyanamide and phosphoric acid. However, the flame retardants disclosed therein by OBrien are not resistant to hard water washing. Similarly, East German Pat. Nos. 15,357 and 18,253. and Schiffner et al. in Faserforsch u. Texiltech., l4, (9), 375-86 1963) describe specific attempts to impart flame resistance to textile material with certain flame retardants, including combinations of urea or dicyandiamide with chloromethyl phosphonic acid, or urea with hydroxymethyl phosphonic acid, which combinations may also not be resistant or durable to repeated cycles of hard water washings, or which may unduly degrade the physical strengths of fabrics.

Other disadvantages include the relatively large quantities (high add-on) which may be necessary in order to impart flame retardance, and the undesirable alteration of other properties of the cellulosic textile material such as color, hand, and susceptibility to dye- Also, many flame retardants are incompatible with commonly employed crease-proofing agents; in the past this limitation has discouraged use of flame retardants in conjunction with a crease-proofing operation so as to yield a textile material which is both flame retardant and wrinkle resistant.

SUMMARY OF THE INVENTION Accordingly, a primary object of the present invention is to render fiber-containing material flame retardant while preventing or substantially alleviating one or more of the above-discussed disadvantages of prior processes.

Another object is to provide an improved process for imparting flame retardancy to cellulosic textile materials which flame retardancy is durable and resistant to multiple household launderings in general and especially in hard water.

Another object is to provide an improved cellulosic flame-retarding process requiring only a relatively small add-on or amount of flame retardants.

A still further object is to provide an improved process for rendering cellulosic textile material flame retardant which does not adversely affect the other properties of the material.

Another object of the present invention is to provide a cellulosic flame-retarding process having improved efficiencies of reaction between the flame retardants and the cellulosic material.

Yet another object is to provide an improved process for rendering cellulosic textile material both flame retardant and wrinkle resistant, with improved dimensional stability.

Yet another object is to provide flame resistant fibrous products produced by these processes.

Additional objects and advantages of the present invention will be apparent to those skilled in the art by reference to the following summary of the characteristic features of the present invention and the subsequent description of the preferred embodiments:

In accordance with a primary aspect of the present invention, a process is provided for rendering cellulosic and wool fiber-containing material flame retardant comprising contacting the material with cyanamide and at least one phosphonic acid represented by the structural formula:

to deposit or fix on the material a flame-retarding amount of the phosphonic acid with cyanamide. In the above formula, R represents a monovalent radical such as hydrogen and R represents a monovalent radical such as methyl or hydrogen.

A central feature of the present invention is the discovery that cyanamide and the above described phosphonic acids can impart durable, hard water washresistant, flame retardancy to cellulosic fibercontaining material, particularly mercerized cotton cloth. In addition, the fire retardancy-imparting systems of the present invention have improved efficiencies in terms of efficiency of reaction between the flame retardants and the cellulose, and in terms of fire retardancy per unit addon of phosphorus.

In accordance with another aspect of the present invention, the fibrous material rendered flame-retardant as indicated above is subsequently treated to improve the durability of flame retardancy to repeated hard water washing by contacting the material with additional cyanamide. Also, this subsequent treatment with additional cyanamide has been found to improve dimensional stability and durable press properties of cellulosic textile material.

In accordance with yet another aspect of the present invention, durability of the flame retardancy of the fibrous material to repeated hard water washing is improved by methylation of the acid form of the phosphonic acid residue on the fibrous material. In a preferred embodiment described below. such methylation is accomplished by contacting the fibrous material with diazomethane.

In accordance with another aspect of the present invention, the fibrous material rendered flame retardant by the phosphonic acid and cyanamide as indicated above is subsequently treated to improve the durability of flame retardancy to repeated hard water washing by contacting the material with at least one water-soluble. compound possessing reactive N-methylol groups. and thereafter curing the material to fix or insolubilize the compound on the material.

Other aspects and advantages of the present invention will be apparent to one skilled in the art from the following:

DESCRIPTION OF THE PREFERRED EMBODIMENTS As indicated above. cyanamide (HNCNH or H NCN). also known as carbodiimide. is used along with certain phosphonic acids to impart the washresistant flame retardancy to the fibrous or fibercontaining material.

The phosphonic acids which may be suitable can be represented by the general structural formula:

where R represents a monovalent radical such as hydrogen or lower alkoxy. and R represents a monovalent radical such as hydrogen or lower alkyl. The alkyl radicals or portions of the radicals may contain, for example. from I to 4 carbon atoms.

Non-limiting examples of phosphonic acids having the above-described structural formula and which may be used according to the process of the present invention including methyl phosphonic acid, methyl phosphonic acid monomethyl ester. methoxymethyl phosphonic acid. and methoxymethyl phosphonic acid monomethyl ester. Mixtures of two or more of the phosphonic acids may be used if desired.

The more preferred phosphonic acids are methyl phosphonic acid and methyl phosphonic acid monomethyl ester. and the most preferred phosphonic acid is methyl phosphonic acid insofar as it has been found to give or impart the most durable flame retardancy to the cellulosic materials.

The manner in which the phosphonic acids and cyanamide are prepared or derived is per se well known and does not form a part of the present invention.

The cellulosic and wool fiber-containing materials which may be treated according to the present invention are generally any of those which have been previously employed in conjunction with known flame retardants. The fiber-containing or textile material can have a wide variety of physical forms and can be fibers. fila merits. yarns. threads, and particularly woven and nonwoven cloth. The cellulosic fiber material can be cotton, flax. linen. hemp. or regenerated cellulose such as rayon (e.g.. viscose rayon). Mercerized cotton may give particularly advantageous results. (Mercerized cotton is well known per se; mercerization typically comprises passing cotton through a to percent solution of sodium hydroxide under tension, and then washing the cotton with water while under tension. Mercerization using liquid ammonia is also known). These fiber-containing or textile materials can be mixtures of two or more different fibers, e.g., a mixture of cellulosic fibers with other fibrous materials such as nylon (e.g.. nylon 6. 6), polyester (e.g., polyethylene terephthalate). acrylics (e.g.. polyacrylonitrile), polyoleflns (e.g.. polypropylene), polyvinyl chloride, polyvinylidene chloride. and polyvinyl alcohol fibers.

The preferred cellulosic textile materials are those containing 50 weight percent or more of cotton and especially pure, i.e.. essentially weight percent, cotton cloth.

According to a broad aspect of the present invention, fire or flame retardancy can be imparted to fibrous material by simply contacting or impregnating the material with the phosphonic acid and cyanamide under widely varying conditions of temperature and pH. However. durable. i.e.. wash resistant, flame retardancy is imparted only by fixing, i.e.. reacting. the phosphonic acid with the cyanamide on the material. This fixing or curing is generally accomplished by heating the treated material at superambient temperatures and at low pH. Broadly, any temperature can be employed above which the phosphonic acid and cyanamide are fixed or reacted on the material and below which undesirable thermal degradation of the material begins, and generally from 20 to 400C and preferably from 100 to 300C. Optimum results are obtained at to 180C.

Durable flame retardance is imparted if, concurrently with the above described heating, the pH of the reacting mixture on the material is low. i.e.. typically less than 2.5 and preferably less than 1.5, e.g.. about 1.0. While these pHs are believed to be critical to durability it is generally valid to assume that the pH of the reacting mixture on the material is the same as the pH of the mixture of phosphonic acid, cyanamide, and solvent when present. except as indicated below for the in situ generation of the reactants.

The fibrous material may be contacted with a simple mixture of the phosphonic acid and cyanamide; and a solvent is preferably present. The solvent can be employed in any amount up to infinite dilution as long as the final treated material has an add-on sufficient to impart flame retardancy. which add-on may be, for example. from 2 to [5 weight percent. Add-on is defined and used herein as the increase (dry basis) in weight of the flbrous material due to the addition of the flame retardant as a percentage of the weight of the untreated fibrous material. Examples of suitable solvents include lower alkanols such as methanol and ethanol, lower alkylene or alkyl ethers such as dioxane and ethyl ether, or, most preferably. water. Such solutions are termed pad baths.

The fibrous material can be contacted with the phosphonic acid and cyanamide sequentially but is preferably contacted with both simultaneously.

This mixture of phosphonic acid and cyanamide can be employed at autogenous pH which is generally about 0.8 or at a slightly higher pH, e.g., about 1.0 to 1.5, except as indicated below for the in situ generation of the reactants where the pH of the pad bath may vary up to about 6.0. Naturally. in the latter case the pH of the pad bath may be quite different than the pH on the material at fixation.

A method by which the above described phosphonic acids can be formed in situ is by the thermal degradation of the corresponding ammonium salt such as monoor di-ammonium methyl phosphonic acid, or ammonium methyl phosphonic acid monomethyl ester. For example, ammonium hydroxide can be added to a pad bath containing the phosphonic acid (which would, of course, raise the pH, typically to about 3.0). Thus, in the fixing step there is initially present, on the fibrous material. cyanamide and an ammonium salt of the phosphonic acid. Upon heating to fixation, the ammonium salt would decompose to ammonia and the corresponding phosphonic acid (resulting in a lowered pH). Usage of such ammonium salts and the inherent raising of the pH of the pad bath can be advantageous where lower pH (higher acidity) pad baths are not desired due to corrosion and personnel handling considerations.

In a preferred process for rendering fibrous materials such as cellulosic textile materials flame retardant according to the present invention, the material is first contacted with an aqueous solution comprising a mixture of phosphonic acid and cyanamide at the desired pH in a molar ratio of 1:10 to :1, preferably l:2 to 3: l and most preferably 1:2 to 2:1. The excess solution is then removed from the material by any suitable means such as by passing the material between the nip of two rollers. The material is then dried to remove ex cess water. The drying can be accomplished at any temperature but is generally accomplished at superambient temperatures and preferably from 20 to 150C. The material is then heated in order to fix the phosphonic acid and cyanamide on the material and is conducted at the above described fixation temperatures. The heating is conducted for at least several seconds and up to several hours. more typically from one to minutes. ln certain instances. the fixing may be generally complete in within 2 to 10 minutes. The drying and heating steps can be conducted simultaneously but are preferably conducted sequentially. The fixing of the phosphonic acid with the cyanamide on cellulosic material is presently thought to occur in the form of a reaction product which then reacts with the hydroxyl groups of the cellulosic material.

The treated fibrous material preferably has sufficient add-on such that it exhibits the desired degree of flame retardancy. Such materials generally have add-ons of l to 30. and preferably 10 to percent.

It is only critical to the present invention that the above described phosphonic acids and cyanamide be present on the fibrous material. Therefore, according to another embodiment of the present invention many of these compounds can be formed in situ. A preferred method by which the above described phosphonic acids can be formed in situ is by the above-described thermal degradation of the corresponding ammonium salt such as ammonium methyl phosphonic acid monomethyl ester. or monoor di-ammonium methyl phosphonic acid. Another method which involves thermally decomposable esters which upon heating yield the above-described phosphonic acids can be employed. Examples of such esters include among others methyl phosphonic acid mono-t-butyl ester and methyl phosphonic acid monomethyl ester mono-t-butyl ester. These compounds thermally decompose to give respectively methyl phosphonic acid and methyl phosphonic acid monomethyl ester. A third method may be by the use of metal salts of the phosphonic acids together with means for creating the low pHs necessary to effect fixation. For example, the pH of the pad bath may be increased with sodium hydroxide, followed by the addition of ammonium chloride. Thus, in the fixing step there would be present on the cellulosic material; cyanamide, a sodium salt of the above described phosphonic acids, and ammonium chloride. upon heating, the ammonium chloride would decompose to ammonia and hydrochloric acid converting the sodium salt to the free acid to accomplish fixation. Naturally, in these cases the pH of the pad may be quite different than the pH on the material.

The solution of phosphonic acid and cyanamide into which the cellulosic material is dipped may also contain, if desired, conventional softeners, lubricants, stiffeners, brighteners, water-repellants, soil release agents, and dyes.

The fibrous material rendered flame retardant as indicated above may be subsequently processed to improve durability of the flame retardancy by treating the material with additional cyanamide, or diazomethane (methylation), or water-soluble compounds possessing reactive N-methylol groups. When such further processing or retreatments" are employed, the acid form of the phosphonic acid residue typically needs to be regenerated such as by contacting or souring" with a dilute hydrochloride acid solution. Such regeneration is typically necessary due to what is thought to be inherent chemical breakdown of cyanamide to produce eventually ammonia in the curing or fixation state, which results in an ammonium salt form of the phosphonic acid residue on the fabric. And after hard water washing, the phosphonic acid residues may inherently be present on the fabric as their calcium salts, as further explained hereinbelow.

After laundering in hard water, the phosphonic acid residues are thought to be at least in part present on the fabric as their calcium salts, e.g.,

O Cellulose H CP(O);

And generally, for a given phosphonic acid the order of flame retardant efficiency (char length) is acid monomethyl ester calcium salt. It is thought that this subsequent retreatment with cyanamide causes further reaction of the phosphonic acid residue with the fibercontaining material, which further reaction lowers ionicity and therefore lowers susceptibility to calcium pickup (increases resistance to ion exchange) during hard water washings. As a consequence, flame retardance, and especially the durability of flame retardance, is improved.

In the case of cellulosic textile materials, the further reaction of the phosphonic acid by the cyanamide is thought to be in the nature of a crosslinking reaction insofar as, surprisingly, dimensional stability or shrinkage control, durable press properties (wrinkle resistance), and overall shape retention and wash/wear properties are also demoonstrably improved.

When cyanamide is used in this subsequent treatment, the acid form of the phosphonic acid residue should be regenerated such as by contacting or souring with a dilute hydrochloric acid solution, and the soured fibrous material is then contacted or impregnated with cyanamide as generally indicated above for the initial flame retardancy treatment. For example. the material may be contacted with a solution of cyanamide. Examples of suitable solvents include methanol. ethanol, dioxane and. most preferably. water. The cyanamide is present in the solution or pad bath in an amount sufficient to improve flame retardancy (or reduce ionicity) as discussed above. For example. the concentration of cyanamide in solution may range from about 1 to 50 weight percent. and more typically. from 10 to 20 weight percent. Higher or lower concentrations may be used if desired.

As in the initial treatment. any excess solution may then be removed from the fibrous material by any suitable means such as by passing the material between the nip of two rollers. The material may then be dried to remove excess water. The drying can be accomplished at any temperature but is generally accomplished at ambient or superambient temperatures. and preferably from 20 to 150C The material with the cyanamide is then heated in order to further react the phosphonic acid residue on the fibrous material. Broadly. any temperature can be employed above which the phosphonic acid residue is further reacted with the material by the cyanamide and below which undesirable thermal degradation of the material begins. and generally from about 50 to 400C. preferably from l to 300C. and most preferably from l20 to 180C. The heating is conducted for at least several seconds up to several hours. more typically from about seconds to 2 hours and preferably from about one to minutes. The drying and heating steps can be conducted simultaneously but are preferably conducted sequentially.

As indicated above. the treated material preferably has sufficient add-on such that it exhibits the desired degree of flame retardancy. Such materials generally have add-ons of about 1 to 30. and preferably about 10 to percent.

When diazomethane is used in the subsequent treatment. the acid form of the phosphonic acid residue should be regenerated such as by contacting or souring" with a dilute hydrochloric acid solution. and the soured fibrous material is contacted with diazomethane as generally indicated above for subsequent treatment with cyanamide. For example. the fibrous material may be contacted. e.g.. immersed. in an ether solution of diazomethane for about l to 2 hours at 0 to C. Such treatment with diazomethane is thought to bring about methylation of the phosphonic acid residue. thus reducing ionicity and calcium pickup (increasing resistance to ion exchange). and improving flame retardancy. especially durable flame retardancy. Other methylating agents such as orthoesters. e.g.. trimethyl orthoformate. may also be used to bring about methylation of the phosphonic acid residue. These methylating agents are well known per se and their production or derivation is not part of the present invention.

When one or more N-methylol compounds are used in the subsequent treatment. the acid form of the phosphonic acid residue should be regenerated such as by contacting or souring' with a dilute hydrochloric acid solution. and the soured fibrous material is contacted with the N-methylol compound and is thereafter cured to fix or insolubilize the compound on the material.

The water-soluble compounds possessing reactive N- methylol groups. sometimes referred to herein as N- methylol compounds, include the substantially water soluble precondensates which are obtained by condensation of formaldehyde with a compound such as melamine or a lower alkylsubstituted melamine, or a urea. The resulting methylol-containing compound or precondensate may be further etherified by reaction with a lower alkanol such as methanol or butanol. As is well known in the fabric treating art. these precondensates are capable of being applied to fibrous materials from an aqueous solution. Good results may be obtained. for example. using precondensates obtained by condensing 1 mole of melamine or an alkyl substituted melamine with l to 6 moles of formaldehyde. i.e.. using mono-. di-, tri-. tetra-. penta-. or hexa-methylol melamine. Such products function well to increase flame retardancy durability and can be readily fixed or cured on fibrous material by heating as described herein. Com mercially available products of this kind include Aerotex 23. an alkylated melamine-formaldehyde precondensate. Aerotex M-3. a dimethoxymethyl hydroxymethyl melamine; Aerotex P-225. a hexakis (methoxymethyl) melamine; Aerotex 19. which is a less completely fractionated modification of Aerotex P-225. and Aerotex 92 which is a melamine having an average of about 1.5 methylol groups. These Aerotex products are supplied by American Cyanamide Companyv Equivalent products are commercially available from other manufacturers such as Monsanto Company which produces Resloom HP. which is a melamine having an average of about 2 to 3 methylol groups. To be applied by padding. one or more of the aforementioned N-methylol compounds may be dissolved in water to form a solution containing from about 1 to 507r. preferably about 5 to 20%. N-methylol compound. To facilitate insolubilization or formation of polymer on the fabric in a desired amount. it may be desirable in certain cases to add to the padding solution. a catalyst such as formic acid. citric acid. hydrochloric acid. or. particularly. an acid-acting salt such as zinc nitrate. zinc chloride. magnesium chloride. ammonium choride. aluminum chloride. sodium hydrogen phosphate. or sodium dihydrogen phosphate. Such a catalyst may be added to the pad bath in a concentration of between about 0.1 and 10% by weight of the N-methylol compound. Formation of the water-insoluble form of the N-methylol compound on the fibrous material is typically aided by heat in addition to acidity. After applica tion of the N-methylol compound to the fibrous material. the latter is dried and finally cured under conditions essentially the same as or similar to those described earlier herein in connection with the subsequent treatment with cyanamide.

Application of the N-methylol compound-containing solution to the fibrous material may be done by conventional padding using customary equipment. or by other processes well known in the art. Typically. the solutions are applied to the fibrous materials in a wet pickup of from about 40 to l20%. so as to give upon fixation an add-on of betweenabout l and 15%, based on dry fabric weight. The padding may be conducted at ambient temperature. e.g.. between about 10 and 30C. As in the initial treatment. any excess solution may then be removed from the fibrous material by any suitable means such as by passing the material between the nip of two rollers. The material may then be dried to remove excess water. The drying can be accomplished at any temperature but is generally accomplished at ambient or superambient temperatures. and

typically from 20 to 100C. The material with the N- methylol compound is then heated in order to fix or insolubilize the N-methylol compound on the fibrous material. Broadly. any temperature can be employed above which the N-methylol compound is reacted on the material and below which undesirable thermal degradation of the material begins, and preferably from 100 to 300C. and most preferably from 120 to 180C. The heating is conducted for at least several seconds up to several hours, more typically from about seconds to 2 hours and preferably from about one to minutes. The drying and heating steps can be conducted simultaneously but are preferably conducted sequentially.

Such treatment with N-methylol compounds has been found to reduce ionicity and calcium pickup (increasing resistance to ion exchange). thus improving durable flame retardancy. Increased durability offlame retardancy through such subsequent treatment with N- methylol compounds was unexpected insofar as the utilization of such compound in the initial pad baths containing the phosphonic acid and cyanamide reduced flame retardancy. Moreover, other conventional creaseproofing agents such as dimethylol dihydroxy ethylene urea have been found not to increase significantly the durability of flame retardancy.

If desired. more than one subsequent treatment with additional cyanamide or diazomethane or NMethylol compound may be used. Combinations of subsequent treatments with diazomethane and N-methylol compound and retreatments with cyanamide may also be used if desired.

The present invention is further illustrated by the following examples; all parts and percentages in the examples as well as in other parts of the specification and claims are by weight unless otherwise indicated. These nonlimiting examples are illustrative of certain embodiments designed to teach those skilled in the art how to practice the invention and to represent the best mode contemplated for carrying out the invention.

EXAMPLE 1 This example illustrates the process of the present invention employing cyanamide and methyl phosphonic acid (MPA) or methoxy methyl phosphonic acid (MMPA) in aqueous solutions of varying acid to cyanamide molar ratios as is shown in TABLE I. Comparison runs 8 to 14 were also made using cyanamide and chloromethyl phosphonic acid (CMPA) or hydroxymethyl phosphonic acid (HMPA) in aqueous solutions of varying acid to cyanamide weight ratios as shown in TABLE I.

For each run. a weighed piece of cotton twill measuring 12 inches X 12 inches was dipped into the aqueous solution or pad bath of cyanamide and phosphonic acid and then passed between the nip of two rollers to remove the excess solution. The cloth was then dried in an oven for 10 minutes at 80C and then cured (fixed) in a second oven for 15 minutes at 160C. The fabric was then washed once as described below. dried. conditioned at 65% relative humidity at 21C and reweighted. The difference between the initial weight of the sample prior to the contact with the solution and final weight of the cloth after one wash divided by the initial weight of the cloth times 100 is recorded in TABLE 1 as add-on." This procedure was repeated for each of the remaining solutions.

Each of the samples was then washed the indicated number of times in an automatic home laundering machine having one wash and two rinses with intermediate spin dry operations. A hard water solution of household laundry detergent, commercially available as ALL Laundry Detergent, was employed as the wash water (pH 8.5). Hard water was employed in the rinses. In this example, the term hard water" refers to Irvine, Calif, water containing a degree of hardness equivalent to 350-380 ppm of calcium carbonate. Total dissolved solids amount to 750-850 ppm. The flame retardancy was then measured according to American Association of Textile Chemists and Colorists (AATCC) procedure 34-1966 and the char length in inches is shown in TABLE I. (The greater the char length, the less the flame retardancy.) A qualitative pass (+)/fai1 vertical strip-match test was also given to each of the treated samples.

As may be seen from TABLE I, at the optimum MPA: cyanamide ratio of 1:2 (run 2) the retardance is durable for at least 250 washes. At an MMPAzcyanamide ratio of 1:2 (run 6) the retardance is durable for at least washes.

TABLE I THE EFFECT OF PHOSPHONIC ACID:CYANAMIDE RATIO ON FLAME RETARDANCE Fill Strength Retention (V1) Run No. Acid Used Cyan-amide AcidzCyanamide Add-On P N C1 ne Wash) in Bath ("/1 Ratio (71) (9?) (71) (71) Tear Tensile 1 MPA 8 1:1 13.6 2.46 0.47 116 58 2 MPA 16 1:2 17.7 3.28 0.61 94 3 MFA 24 1:3 17. 2.94 0.87 97 55 4 MPA 48 1:6 14.6 2.25 1.42 127 64 5 MMPA 8 1:1 10.2 1.62 0.52 n MMPA 16 1:2 16.] 2.54 0.71 7 MMPA 24 1:3 17.1 2.42 0.87 8 CMPA 8 1:1 12.2 1.89 0.70 1.95 71 43 9 CMPA 16 1:2 16.8 2.49 1.01 2.24 67 63 10 CMPA 24 1:3 17.8 2.53 1.49 1.60 87 56 ll CMPA 32 1:4 20.4 2.46 2.72 1.22 72 55 12 CMPA 48 1:6 24.0 2.25 3.30 1.08 77 (50) l3 HMPA 8 1:1 11.4 2.17 0.80 l4 HMPA 16 1:2 18.7 3.16 0.90

Flame Retardance =Char Length (in.) and Match Test at Number of Washes Shown ("ALL Detergent) Run No. 1 5 10 20 40 50 250 1 2 /2 3V4 3% BEL 2 1%("1'1 21+) 2 Z Z 2% 2% 2 /4() 2% 3 1% 2 4(1) /2 (i) 3% 2% 2% 2 /2 BEL TABLE IContinued Flame Retardance Char Length (in.) and Match Test at Number of Washes Shown (ALL Detergent) The hath also contalned. in addition to the cyanamtde and phosphonic acid. 0.1 percent Triton X-lUU non-tonic wetting agent and percent Velvamine 3X0 polyethylene softencn. Value in parentheses measured in area of char "(4-) passed match test. (-l failed match lest. (:1 burned greater than 1 inches but not entire length. In a substantially duplicate run when: higher percentages ol P. N and Cl ere recorded. as well as a loner degree of lonicity. the flame retardance at fifty washes was EXAMPLE 11 Quantity lngredient Grams Moles methyl phosphonic acid 8 0.5 cyanamide (84g of 50 wt. '4 42 1.0

aqueous solution 1 The phosphonic acid and cyanamide were mixed with an amount of water added to the mixture to give a total volume of 300 ml of solution containing 30 percent solids and having a pH of 0.8. This solution was divided into six 50 ml samples and the pH of each adjusted to the value shown in Column 2 of TABLE ll of the following table with 50 wt. r NaOH.

For each run. a weighed piece of cotton twill measuring 12 inches X 12 inches was dipped into a solution sample and then passed between the nip of two rollers to remove the excess solution. The cloth was then dried in an oven for minutes at 80C and then cured in a second oven for minutes at 160C. The fabric was then washed once as described below, dried, conditioned at 65 percent relative humidity at 21C and re weighed. The difference between the initial weight of the fabric sample prior to the contact with the solution and final weight of the cloth after one wash divided by the initial weight of the cloth times 100 is recorded at Column 3 of TABLE II, as add-0n. This procedure was repeated for each of the remaining solutions.

Each of the fabric samples was then washed the indicated number of times in an automatic home laundering machine having one wash and two rinses with intermediate spin dry operations. A hard water solution of alkyl benzene sulfonate, commercially available as "Sears Super-concentrated Laundry Detergent, was employed as the wash water (pH 10.3). Hard water was employed in the rinses. The flame retardancy was then measured according to American Association of Textile Chemists and Colorists (AATCC) procedure 34-1966 and the char length in inches is shown in C01- umns 4 through 8 of TABLE 11. (The greater the char length. the less the flame retardancy.)

As may be seen from TABLE II, at a pH of 1.0 (run 15) the flame retardance was durable for at least washes.

TABLE 11 THE EFFECT OF pH ON FLAME RETARDANCE lMETHYL PHOSPHONIC AClDzCYANAMlDE) Flame Retardance after Indicated Number 0 ashes AATCC 34-1966 (length of char) Add On one five ten twenty thirty Run 1 Approx.) wash washes washes washes washes No. pH (WU/1! (in.) (in) (in.) (in.) (in.)

15 1.0 9.1 2 /2 4 4 3% 4 16 1.5 8.3 2% 4% 4% 4% BEL 17 2.0 8.2 3% BEL 18 2.5 5.0 3% BEL 19 3.0 4.3 BEL 30 3.5 2.3 BEL Legend BEL burned entire length EXAMPLE III This example illustrates certain preferred embodiments of the present invention employing cyanamide with methyl phosphonic acid monomethyl ester and gives a comparison to the use of cyanamide with chloromethyl phosphonic acid monomethyl ester.

The procedure of Example 11 is repeated employing the same quantities of the same ingredients and the same times, procedures and conditions with the excepparison to the effect of mercerization of the cotton (flannel) fabric.

The procedure of Example 1, run 2, is repeated employing the same quantities of the same ingredients and tion that the methyl phosphonic acid is replaced by the same times, procedures and conditions with the exmethyl phosphonic acid monomethyl ester in runs ception that unmercerized flannel cloth (Barium No. 21-24 and with chloromethyl phosphonic acid monolOO) was used for run 28 and mercerized flannel cloth methyl ester in comparison runs 25-27, with varying (Barium No.l54) was used in run 29, and except that percentages of acid and cyanamide in the bath. Data soft water (Menlo Park, California) containing a deand results are recorded in TABLE III. In TABLE III gree of hardness equivalent to 20 ppm of calcium carthe values in Column 12 are calculated by the formula: bonate was used instead of the Irvine water. The results Fill 100 Tensile strength after treatment are recorded In TABLE IV- Strength Tensile strength before treatment AS may be seen from TABLE IV, the flame retardancy for the mercerized flannel (run 29 was durable for The values of tensile strength are determined according 15 at least 50 washes. to ASTM D1682-59T and are measured in the "fill" di- Mercerization of cotton is believed to increase the rection of the material. The fill direction is also known number of anhydroglucose units available for reaction, as the direction parallel to the woof threads. i.e., removes them from relatively inpenetrable crys- As may be seen from TABLE III, at a pH of from 0.5 talline regions of the cellulose. Thus, when a given to 1.0 (runs 21-22), flame retardance was durable for amount of flame retardancy-imparting reactants is apat least 50 washes for methyl phosphonic acid monoplied to the cellulose, the concentration of reactive methyl ester. sites on a mercerized fabric is greater relative to a simi- TABLE III FLAME RETARDANCE OF MPAMzCYANAMIDE AND CMPAMcCYANAMlDE SYSTEMS Flame Retardance after Indicated Number of Washes AATCC 34-1966 (length of char) one five twenty thirty forty fifty Fill Run Acid in Cyanamide Add On wash washes washes washes washes washes Strength No. Acid Lsed Bath (9 in Bath (91) pH (wt "/1) (in.) (in.) (in.) (in.) (in.) (in.) Retention (7:)

21 MPAM 33 0.5 12.2 3 3% 4% 72 22 MPAM 33 25 1.0 11.2 3 3% 3 /4 4 4 23 MPAM 31 24 2.0 11.1 3 /2 4 4 /2 BEL 94 24 MPAM 31 24 3.0 8.1 4 BEL 25 CMPAM 41 24 1.0 16.4 2% 3% 4V2 BEL 26 CMPAM 38.5 2.5 2.0 110 3 /2 BEL 17 CM PAM 36 21 3.0 9.0 4% BEL Legend MPAM methyl phosphonic acid monomethyl ester (MPAM chloromethyl phosphonic acid monomethyl ester BEL burned entire length EXAMPLE IV This example illustrates certain preferred embodiments of the present invention employing cyanamide lar but unmercerized fabric, and hence, the efficiency of immobilization is increased (i.e., wash-off is decreased). This phenomena is significant insofar as efficiencies of reactants, durability of flame retardancy,

with methyl phosphonic acid (MPA) and gives a and overall process economies are improved.

TABLE IV EFFECT OF MERCERIZATION ON FLAME RETARDANC E (METHYL PHOSPHONIC AClDzCYANAMIDE) Flame Retardance After Indicated Number of Washes AATCC 34-1966 (length of char) Add On N071) PW!) Run No. Acid Used (wt "/1) Mercerized (One Wash) (One Wash) One Wash (in.) Fifty Washes (in.)

28 MPA 15.7 No 048 3.26 2% BEL 29 MPA 25.4 Yes 0.65 4.18 1% 2 legend BFl. burned entire length I passed match test (1 l'alled match test EXAMPLE v This example illustrates certain preferred embodiments of the present invention employing cyanamide and methyl phosphonic acid (MPA) with one or more retreatments with additional cyanamide.

Five pieces of cottom twill were dipped into an aque ous solution containing 18 weight percent methyl phosphonic acid. 16 weight percent cyanamide. 0.1 weight percent Triton X-l non-ionic wetting agent and weight percent Velvamine 380 polyethylene softener. The fabric samples were then dried in an oven for minutes at 80C and then cured in a second oven for minutes at 160C. The fabric samples were then washed, dried and conditioned as described in Example I except that the Sears detergent employed in Example 11 was usedv One fabric sample was used as acontrol. while the remaining four fabric samples were subjected to from 1 to 4 retreatment operations with additional equivalent to 350-380 ppm of calcium carbonate. Total dissolved solids amount to 750-850 ppm. The flame retardancy was then measured according to American Association of Textile Chemists and Colorists (AATCC) procedure 34-1966 and the char length in inches is shown in TABLE 1. (The greater the char length. the less the flame retardancy.) Durable press properties were measured according to AATCC 88A 1964T. Ionicity was measured by souring the fabric with dilute hydrochloric acid, rinsing the fabric with distilled water and then titrating with sodium hydroxide solution. Titration was effected by placing the fabric in a vessel of distilled water and monitoring by conventional potentiometer technique. The results are tabulated in TABLE V.

As may be seen from TABLE V, durable flame re tardance. dimensional stability and durable press prop erties were all improved by retreatment with cyana mide.

TABLE V RETREATMENT OF MPA CYANAMIDE TREATED FABRICS WITH ADDITIONAL CYANAMIDE Run No. v lurnher of Retreatments Flame Retardance Warp Shrinkage 1) l wash 50 washes I wash 50 washes (control) 0 W4 BEL 8 14 3| 1 31+) l /q(+| 2.5 7 32 I lVzt-t-l 1 /21:) 2 (i 33 3 1 (+1 1 /4 1: 1.5 4 34 4 1/4(+i 1 41+: l 3.5

Analyses Pt "/1 N071) lonicity DP Rating Run No. l wash 50 washes I wash 50 washes l wash 50 washes I wash 50 washes 30 (control) 2.89 .73 0.64 0.53 0.75 0.74 2 2 31 3.95 .78 1.38 1.13 0.56 0.60 3.5 2 32 1.92 .74 1.83 1.51 0.44 0.52 4 2.5 33 1.93 2.75 1.16 1.75 0.37 0.47 4 3 34 2.98 2.81 2.48 1.97 0.33 0.46 4 3.5

EXAMPLE VI cyanamide to improve durable fire retardancy (reduce ionicity) and to improve also the durable press properties of the fabric. Each retreatment operation included souring the fabric sample with a dilute hydrochloric acid solution and then dipping the fabric sample into an aqueous solution containing 16 weight percent cyanamide. 0.1 weight percent Triton X-l00 non-ionic wetting agent and 5 weight percent Velvamine 380 polyethylene softener. The fabric samples were then dried in an oven for 10 minutes at 80C and then cured in a second oven for 15 minutes at 160C. Each of the fabric samples were washed the indicated number of times in an automatic home laundering machine having one wash and two rinses with intermediate spin dry operations. Hard water was employed in the washes and rinses. In this example. the term hard water" refers to Irvine. Calif. water containing a degree of hardness This example illustrates certain preferred embodiments of the present invention employing cyanamide and methyl phosphonic acid with one or more diazomethane (CH N retreatments to improve durable flame retardance.

The procedure of Example V was repeated employing the same quantities of the same ingredients and the same times. procedures and conditions with the exception that diazomethane retreatments were used on two fabric samples instead of the cyanamide retreatment. The diazomethane retreatment consisted of soaking the soured fabric sample in an ether solution containing about 2.5 weight percent diazomethane for approximately 12 hours at about 25C. The results are shown in TABLE VI.

TABLE VI THE EFFECT OF DIAZOMETHANE RETREATMENT IIMETHYLATION) ON MPA CYANAMIDE TREATED FABRICS Number of Analyses 2 Flame Retardance Ionicity Pt7r) N(7r) Run No. Treatments 1 wash 50 washes I wash 50 washes I Wash 50 washes I wash 50 washes 35 (control) 0 I 0.73 1.69 0.57 36 1 3 1+1 2 (:1 0.39 0.40 37 2 3 1+) 2 (:1 0.07 0.12 2.64 2.63 0.47 0.45

17 18 EXAMPLES VIl VIII dures and conditions with the exception that the pH of the phosphonic acid-containing pad bath was adjusted These examples illustrate certain preferred embodito a pH of 3 using ammonium hydroxide; mercerized ments of the present invention employing cyanamide flannel was used instead of cotton twill; and the hardwith methyl phosphonlc acid on wool (runs 38 and 39) ness equivalent of the wash and rinse water was 40 ppm and on rayon (run 40) fabrics. calcium carbonate (Menlo Park, California). The re- The procedure of Example I (run 2) is repeated emsulting flame retardancy values are shown in TABLE ploying the same quantities of the same ingredients and X.

TABLE X RETREATMENT OF MPA CYANAMIDE TREATED FABRICS WITH ADDITIONAL CYANAMIDE Flame Retardancc after Indicated Number oi'W-ashes AATCC 34-1966 (length of char) Run No. Number of Retreatmcnts One Wash (in.) Fifty Washes (in.)

45 0 1% (i) BEL the same times, procedures and conditions with the ex- EXAMPLE XI ception that the cottom twill was replaced by bleached, undyed wool in run 38, by dyed wool (grey) in run 39, This example illustrates certain preferred embodiand by rayon twill in run 40. The results are recorded ments of the present invention employing cyanamide in TABLE VII. and methyl phosphonic acid with retreatments of N- TABLE VII TREATMENT OF WOOL AND RAYON WITH MPA CYANAMIDE (1:2)

Flame Retardance Run No. Fabric Add-On I wash 5 washes l0 washes 50 washes 38 Bleached. undyed wool 11.271 l% l J9 Dyed Wool (grey) 13.5% 2 /2 3 5 it) Rayon twill 18.9% l (i) 1 /4 (1-) 2 2% EXAMPLE IX methylol compound to improve the durability of the flame retardancy. This example illustrates the present invention when Th procedure of E ample V is repeated employing cyanamide and methyl phosphonic acid are applled t0 the same quantities of the same ingredients and the a fabric from a pad bath ch 1150 Contains flmmO- same times, procedures and conditions with the excepnium hyroxide to increase the otherwise autogenous ti that the cy namide is replaced with a N-methylol pH of the bath to a pH of 5. and the results hat are compound in the retreatment bath (16% Aerotex 92 achieved using various curing times. methylolated melamine).

The procedure of Example I as ep p y- Further improvement in durability of flame retarding the same quantities of the same ingredients and the array i b d, same times, procedures and conditions with the excep- Th i i l f r d mb diment and modes of tion that the pH of the pad bath in each run as adoperation of the present invention have been described juSted to 21 pH Of 5 with amm nium hydroxid an the in the foregoing specification. The invention which is fabric samples were dried at about 5C f r 8 m n intended to be protected herein, however, is not to be and Cured at about 160C or a us es 115 Show in construed as limited to the particular forms disclosed, TABLE The resulting flame remrdancy Values are since these are to be regarded as illustrative rather than also shown in TABLE IX. restrictive. Variations and changes may be made by As may be Seen from TABLE IX. gOOd flame reti dthose skilled in the art without departing from the spirit ancy was achieved in all runs. of the present invention.

TABLE IX FLAME RETARDANCE OF METHYL PHOSPHONIC AClDcCYANAMIDE SYSTEMS AT VARYING CURE TIMES Flame Retardance after Indicated Number of Washes AATCC 34-1966 (length of char) Run No. pH of Bath Curing Times (min.) One Wash (in.) Fifty Washes (in.)

4] 5 2.5 3 3 (I 12 5 5 2 /2 2 /2 43 5 10 2 /4 2 /4 44 5 l5 2V2 2% EXAMPLE X We claim:

1. A process for rendering cellulosic and wool fiber- Example V was repeated employing the same quanticontaining material flame retardant, which process ties of the same ingredients and the same times, procecomprises contacting the material with cyanamide and at least one phosphonic acid represented by the structural formula:

H O OH 1 R c P it on wherein R represents a monovalent radical selected from the group consisting of hydrogen and lower alkoxy; and wherein R represents a monovalent radical selected from the group consisting of hydrogen and lower alkyl. to deposit on the material a flame retarding amount of the phosphonic acid with cyanamide.

2. A process according to claim 1 wherein the material is cellulosic and the phosphonic acid is methyl phosphonic acid.

3. A process according to claim 1 for rendering cellulosic fiber-containing material flame retardant. which process comprises contacting and fixing on the material with cyanamide a flame retarding amount of at least one phos phonic acid represented by the structural formula:

wherein R represents a monovalent radical selected from the group consisting of hydrogen and methoxy; and wherein R represents a monovalent radical selected from the group consisting of hydrogen and methyl; and wherein during contacting the molar ratio of phosphonic acid to cyanamide is from l:lto 10:1.

4. A process according to claim 3 wherein the material is fixed by heating the material for a period of time and at a temperature at least sufficient to give an addon of from l to 30 percent; wherein the phosphonic acid and cyanamide are in solution when contacted with the material; wherein the pH at fixation is less than 2.5; and wherein the cellulosic fiber-containing material is cotton cloth.

5. A process according to claim 3 wherein the cellulosic fiber-containing material is fixed by contacting the material with the phosphonic acid and cyanamide and then heating the material at a temperature between about 100 and 300C.

6. A process for rendering cellulosic textile material flame retardant comprising in sequence the steps of:

l contacting the material with an aqueous solution of cyanamide and at least one phosphonic acid selected from the group consisting of methyl phosphonic acid and methyl phosphonic acid monomethyl ester, wherein the moler ratio of phosphonic acidzcyanamide is [:10 to lOzl. and

ll. heating the material to fix the phosphonic acid with cyanamide on the material to give an add-on of between about 1 and 30 percent.

7. A process according to claim 6 for rendering cellulosic fiber-containing textile material durably flame retardant. which process comprises in sequence the steps of:

l. contacting the material with an aqueous mixture of cyanamide and methyl phosphonic acid wherein the molar ratio of phosphonic acidzcyanamide is 1:10 to l0:l, and;

ll. fixing the retardancy in the material at a pH less than 2.5 by heating the material until an add-on of between about 1 and 30 percent is achieved and the flame retardancy becomes durable to at least 30 hard water washes.

8. A process according to claim 7 wherein the cellulosic material is mercerized cotton cloth and the flame retardancy is durable to at least hard water washes.

9. A process according to claim 7 wherein the aqueous mixture of cyanamide and methyl phosphonic acid further contains ammonium hydroxide, and an ammonium salt of the phosphonic acid is deposited on the textile material.

10. A process for rendering cellulosic and wool flbercontaining material durably flame retardant, which process comprises the steps of:

I. contacting the material with cyanamide and at least one phosphonic acid represented by the structural formula:

H O OH R c' 1' wherein R represents a monovalent radical selected from the group consisting of hydrogen and lower alkmy; and wherein R represents a monovalent radical selected from the group consisting of hydrogen and lower alkyl. to deposit on the material a flame retarding amount of the phosphonic acid with cyanamide; and subsequently.

ll. contacting the material with at least one member selected from the group consisting of cyanamide, diazomethane and water-soluble compounds possessing reactive N-methylol groups. in an amount sufficient to improve the durability of the flame retardancy of the material to repeated hard water washing.

11. A process according to claim 10 wherein in step (I) the phosphonic acid and the cyanamide are in solution when contacted with the material and the molar ratio of phosphonic acid to cyanamide is from 1:10 to 10: l and in step (ll) the cyanamide is in solution when contacted with the material, and the material is thereafter heated to give a total add-on of from l to 30 percent.

12. A process for rendering cellulosic textile material durably flame retardant and wrinkle resistant, which.

process comprises the steps of:

l. contacting the material with an aqueous mixture of cyanamide and at least one phosphonic acid selected from the group consisting of methyl phosphonic acid and methyl phosphonic acid monomethyl ester. wherein the molar ratio of phosphonic acidzcyanamide is 1:10 to 10:1. and

II. heating the material to fix at a pH less than 2.5 the phosp honic acid with cyanamide on the material to give and add-on of between about 1 and 30 percent, and

III. contacting the material with an aqueous solution of cyanamide and heating the material to improve the durability of the flame retardancy, dimensional stability. and durable press properties of the material.

13. A process according to claim 12 for rendering cotton fiber-containing textile material durably flame retardant and for simultaneously improving the dimensional stability and durable press properties of the textile material, which process comprises in sequence the steps of:

l. contacting the material with an aqueous solution of cyanamide with methyl phosphonic acid wherein the molar ratio of phosphonic acidzcyanamide is 1:10 to 10:1,

lI. fixing the retardancy in the material at a pH less than [.5 by heating the material until an addon of between about l and 30 percent is achieved and the flame retardancy becomes durable to at least 30 hard water washes; and

Ill. regenerating an acid form of fixed phosphonic acid residue on the material and then contacting the material with an aqueous solution of cyanamide and heating the material to improve the durability of the flame retardancy to at least 50 hard water washes, and to improve dimensional stability, and durable press properties of the material.

14. A process for rendering cellulosic textile material durably flame retardant, which process comprises the steps of:

l. contacting the material with an aqueous mixture of cyanamide and at least one phosphonic acid selected from the group consisting of methyl phosphonic acid and methyl phosphonic acid monomethyl ester, wherein the molar ratio of phosphonic acid:cyanamide is l:l to :1, and

ll. heating the material to fix the phosphonic acid at a pH less than 2.5 with cyanamide on the material to give an add-on of between about 1 and 30 percent, and

Ill. contacting the material with an aqueous solution of at least one water-soluble compound possessing reactive N-methylol groups and curing the material to improve the durability of the flame retardancy of the material.

15. A process according to claim 14 for rendering cotton fiber-containing textile material durably flame retardant, which process comprises in sequence the steps of:

I. contacting the material with an aqueous solution of cyanamide with methyl phosphonic acid wherein the molar ratio of phosphonic acidzcyanamide is l:lO to 10:1,

ll. fixing the retardancy in the material at a pH less than 1.5 by heating the material until an add-on of between about 1 and 30 percent is achieved and the flame retardancy becomes durable to at least 30 hard water washes; and

Ill. regenerating an acid form of fixed phosphonic acid residue on the material and then contacting the material with an aqeuous solution of the N- methylol compound, and heating the material to cure and the durability of the flame retardancy is improved to at least 50 hard water washes.

16. A process according to claim 15 wherein the textile material is mercerized cotton cloth, and wherein the aqueous mixture of cyanamide and methyl phosphonic acid further contains ammonium hydroxide, and an ammonium salt of the phosphonic acid is deposited on the textile material.

17. A flame retardant material produced according to the process of claim 1.

18. A durably flame retardant material produced according to the process of claim 7.

19. A durably flame retardant material produced according to the process of claim 10.

20. A durably flame retardant and wrinkle resistant material produced according to the process of claim 13.

21. A durably flame retardant material produced according to the process of claim 15.

:k l l 

1. A PROCESS FOR RENDERING CELLULOSIC AND WOOL FIBERCONTAINING MATERIAL FLAME RETARDANT, WHICH PROCESS COMPRISES CONTACTING THE MATERIAL WITH CYANAMIDE AND AT LEAST ONE PHOSPHONIC ACID REPRESENTED BY THE STRUCTURAL FORMULA:
 2. A process according to claim 1 wherein the material is cellulosic and the phosphonic acid is methyl phosphonic acid.
 3. A process according to claim 1 for rendering cellulosic fiber-containing material flame retardant, which process comprises contacting and fixing on the material with cyanamide a flame retarding amount of at least one phosphonic acid represented by the structural formula:
 4. A process according to claim 3 wherein the material is fixed by heating the material for a period of time and at a temperature at least sufficient to give an add-on of from 1 to 30 percent; wherein the phosphonic acid and cyanamide are in solution when contacted with the material; wherein the pH at fixation is less than 2.5; and wherein the cellulosic fiber-containing material is cotton cloth.
 5. A process according to claim 3 wherein the cellulosic fiber-containing material is fixed by contacting the material with the phosphonic acid and cyanamide and then heating the material at a temperature between about 100* and 300*C.
 6. A process for rendering cellulosic textile material flame retardant comprising in sequence the steps of: I. contacting the material with an aqueous solution of cyanamide and at least one phosphonic acid selected from the group consisting of methyl phosphonic acid and methyl phosphonic acid monomethyl ester, wherein the moler ratio of phosphonic acid: cyanamide is 1:10 to 10:1, and II. heating the material to fix the phosphonic acid with cyanamide on the material to give an add-on of between about 1 and 30 percent.
 7. A process according to claim 6 for rendering cellulosic fiber-containing textile material durably flame retardant, which process comprises in sequence the steps of: I. contacting the material with an aqueous mixture of cyanamide and methyl phosphonic acid wherein the molar ratio of phosphonic acid:cyanamide is 1:10 to 10:1, and; II. fixing the retardancy in the material at a pH less than 2.5 by heating the material until an add-on of between about 1 and 30 percent is achieved and the flame retardancy becomes durable to at least 30 hard water washes.
 8. A process according to claim 7 wherein the cellulosic material is mercerized cotton cloth and the flame retardancy is durable to at least 50 hard water washes.
 9. A process according to claim 7 wherein the aqueous mixture of cyanamide and methyl phosphonic acid further contains ammonium hydroxide, and an ammonium salt of the phosphonic acid is deposited on the textile material.
 10. A process for rendering cellulosic and wool fiber-containing material durably flame retardant, which process comprises the steps of: I. contacting the maTerial with cyanamide and at least one phosphonic acid represented by the structural formula:
 11. A process according to claim 10 wherein in step (I) the phosphonic acid and the cyanamide are in solution when contacted with the material and the molar ratio of phosphonic acid to cyanamide is from 1:10 to 10:1; and in step (II) the cyanamide is in solution when contacted with the material, and the material is thereafter heated to give a total add-on of from 1 to 30 percent.
 12. A process for rendering cellulosic textile material durably flame retardant and wrinkle resistant, which process comprises the steps of: I. contacting the material with an aqueous mixture of cyanamide and at least one phosphonic acid selected from the group consisting of methyl phosphonic acid and methyl phosphonic acid monomethyl ester, wherein the molar ratio of phosphonic acid: cyanamide is 1:10 to 10:1, and II. heating the material to fix at a pH less than 2.5 the phosphonic acid with cyanamide on the material to give and add-on of between about 1 and 30 percent, and III. contacting the material with an aqueous solution of cyanamide and heating the material to improve the durability of the flame retardancy, dimensional stability, and durable press properties of the material.
 13. A process according to claim 12 for rendering cotton fiber-containing textile material durably flame retardant and for simultaneously improving the dimensional stability and durable press properties of the textile material, which process comprises in sequence the steps of: I. contacting the material with an aqueous solution of cyanamide with methyl phosphonic acid wherein the molar ratio of phosphonic acid:cyanamide is 1:10 to 10:1, II. fixing the retardancy in the material at a pH less than 1.5 by heating the material until an add-on of between about 1 and 30 percent is achieved and the flame retardancy becomes durable to at least 30 hard water washes; and III. regenerating an acid form of fixed phosphonic acid residue on the material and then contacting the material with an aqueous solution of cyanamide and heating the material to improve the durability of the flame retardancy to at least 50 hard water washes, and to improve dimensional stability, and durable press properties of the material.
 14. A process for rendering cellulosic textile material durably flame retardant, which process comprises the steps of: I. contacting the material with an aqueous mixture of cyanamide and at least one phosphonic acid selected from the group consisting of methyl phosphonic acid and methyl phosphonic acid monomethyl ester, wherein the molar ratio of phosphonic acid: cyanamide is 1:10 to 10:1, and II. heating the material to fix the phosphonic acid at a pH less than 2.5 with cyanamide on the material to give an add-on of between about 1 and 30 percent, and III. contacting the material with an aqueous solution of at least one water-soluble compound possessing reactive N-methylol groups and curing the material to improve the durability of the flame retardancy of the material.
 15. A process according to claim 14 for rendering cotton fiber-containing textile material dUrably flame retardant, which process comprises in sequence the steps of: I. contacting the material with an aqueous solution of cyanamide with methyl phosphonic acid wherein the molar ratio of phosphonic acid:cyanamide is 1:10 to 10:1, II. fixing the retardancy in the material at a pH less than 1.5 by heating the material until an add-on of between about 1 and 30 percent is achieved and the flame retardancy becomes durable to at least 30 hard water washes; and III. regenerating an acid form of fixed phosphonic acid residue on the material and then contacting the material with an aqeuous solution of the N-methylol compound, and heating the material to cure and the durability of the flame retardancy is improved to at least 50 hard water washes.
 16. A process according to claim 15 wherein the textile material is mercerized cotton cloth, and wherein the aqueous mixture of cyanamide and methyl phosphonic acid further contains ammonium hydroxide, and an ammonium salt of the phosphonic acid is deposited on the textile material.
 17. A flame retardant material produced according to the process of claim
 1. 18. A durably flame retardant material produced according to the process of claim
 7. 19. A durably flame retardant material produced according to the process of claim
 10. 20. A durably flame retardant and wrinkle resistant material produced according to the process of claim
 13. 21. A durably flame retardant material produced according to the process of claim
 15. 